The formulation of food and beverage products, particularly aqueous-based food and beverage products, can be difficult. For example, it is frequently necessary to incorporate water immiscible components, such as colors, flavors, nutrients, nutraceuticals, therapeutic agents, or antioxidants, into compositions which are primarily aqueous based. The difficulty of this task is increased by the fact that the compositions need to be formulated such that they are esthetically pleasing to the consumer. For example, it is frequently necessary to incorporate a water-insoluble material into an aqueous beverage while still maintaining the optical clarity of the beverage. These compositions also need to exhibit long-term shelf stability under typical food and beverage shipping, storage and use conditions.
One way that the industry has attempted to satisfy these conflicting requirements is to incorporate the water immiscible materials using microemulsions. A microemulsion is a dispersion of two immiscible liquids (one liquid phase being “dispersed” and the other being “continuous”) in which the individual droplets of the dispersed phase have an average radius less than about one-quarter the wavelength of light. Such microemulsions have also been termed “nanoemulsions”. Typically, in a microemulsion, the dispersed phase droplets have a radius of less than about 1400 Å, and preferably on the order of about 100 to about 500 Å. The basic theory of microemulsions is more fully described in Rosano, Journal of the Society of Cosmetic Chemists, 25: 609-619 (November, 1974), incorporated herein by reference.
Microemulsions can be difficult to formulate, frequently requiring the use of co-solvents, such as ethanol or propylene glycol. These co-solvents can lead to off-flavors in the final product. Further, the formation of microemulsions frequently requires some rather stressful processing conditions, such as high pressure homogenization, which require specialized equipment and can increase the cost of the final product.
It therefore would be useful to have a procedure for formulating microemulsions, using relatively low levels of food grade emulsifiers, which allow the incorporation of water-immiscible components into aqueous-based food and beverage compositions without requiring the use of such co-solvents and relatively extreme processing conditions.
The prior art describes the formation of microemulsions, as well as the use of microemulsions formed by conventional processes for the incorporation of materials into food and beverage products.
U.S. Pat. No. 4,146,499, Rosano, issued Mar. 27, 1979, describes an oil-in-water microemulsion which utilizes a high/low HLB surfactant mixture for forming the emulsion. The patent does not teach or suggest use of a ternary (high/low/medium HLB) surfactant system in forming the emulsion.
U.S. Pat. No. 4,752,481, Dokuzovic, issued Jun. 21, 1988, describes a flavored chewing gum product which includes a chewing gum base, a sweetener, and a flavor-containing emulsion. The emulsion comprises 19 to 59% of a flavoring oil, 1 to 5% of an emulsifier having an HLB of from about 1.6 to about 7.0, and an alkyl polyol (for example, glycerin or polyethylene glycol).
U.S. Pat. No. 4,835,002, Wolf et al., issued May 30, 1989, describes a microemulsion of an edible essential oil (such as citrus oil) in a water/alcohol matrix. The composition comprises water, the essential oil, alcohol and a surfactant. The surfactant component utilized must include a high HLB surfactant, although a mixture of high HLB and low HLB surfactants can also included. There is no disclosure of a ternary surfactant emulsifier system for use in forming the emulsion.
U.S. Pat. No. 5,320,863, Chung et al, issued Jun. 14, 1994, describes microemulsions used to deliver high concentrations of flavor or fragrance oils. The compositions are said to exhibit high stability even in the absence of lower alcohols. The compositions include a nonionic surfactant (generally not edible or food grade); no discussion of HLB criticality is provided. There is no disclosure or suggestion to combine high, low and medium HLB surfactants into a ternary emulsifying system.
U.S. Pat. No. 5,447,729, Belenduik et al, issued Sep. 5, 1995, describes a particulate pharmaceutical composition wherein a pharmaceutical active material may be incorporated into particles in the form of a microemulsion. The outer layers of the particles have hydrophobic/lipophilic interfaces between them. The disclosed compositions can include polysorbate 80 or glycerol monooleate as an emulsifier. There is no teaching in the patent of a ternary surfactant emulsifier system.
U.S. Pat. No. 5,948,825, Takahashi et al., issued Sep. 7, 1999, describes water-in-oil emulsions of hard-to-absorb pharmaceutical agents for use in topical or oral administration. There is no disclosure or suggestion of a ternary surfactant emulsifier system. The emulsifiers disclosed in the '825 patent can include a mixture of two types of nonionic surfactants, one having an HLB of from 10 to 20, and the other having an HLB from 3 to 7.
U.S. Pat. No. 6,048,566, Behnam et al., issued Apr. 11, 2000, describes a nonalcoholic, clear beverage which incorporates from 10 to 500 mg/l of ubiquinone Q10, together with a polysorbate stabilizer.
U.S. Pat. No. 6,077,559, Logan et al., issued Jun. 20, 2000, relates to flavored vinegars which are based on the inclusion of specifically defined microemulsions. The oil-in-vinegar microemulsions comprise from 20% to 70% vinegar, 5% to 35% ethanol, 0.1% to 5% of a flavor material, and 0.5% to 5% of a surfactant. The surfactants utilized are high HLB surfactants; they can also include a small amount of low HLB (4 to 9) surfactant. There is no disclosure of a ternary surfactant emulsifier system in the '559 patent.
U.S. Pat. No. 6,146,672, Gonzalez et al., issued Nov. 14, 2000, relates to spreadable water-in-oil emulsions which are used as fillings in pastry products, particularly frozen pastries. The fillings are said to exhibit enhanced shelf-life and stability. The described emulsions include a mixture of high and low HLB emulsifiers. Although the '672 patent describes a mixture of high and low HLB surfactants, it does not disclose or suggest the ternary surfactant emulsifier system which is utilized in the present invention. Further, the '672 patent does not teach microemulsions or the use of an emulsion to incorporate water-insoluble materials into food products.
U.S. Pat. No. 6,303,662, Nagahama et al., issued Oct. 16, 2001, describes microemulsions used in the delivery of fat-soluble drugs. The disclosed compositions require a high polarity oil, a low polarity oil, a polyglycerol mono fatty acid ester, and a water-soluble polyhydric alcohol. There is no disclosure of a ternary surfactant emulsifier system.
U.S. Pat. No. 6,376,482, Akashe et al., issued Apr. 23, 2002, describes mesophase-stabilized compositions which incorporate plant sterols as cholesterol-lowering agents. The compositions can include a mixture of a surfactant having an HLB of from 6 to 9, a surfactant having an HLB of from 2 to 6, and a surfactant having an HLB of from 9 to 22. Although this patent does teach a ternary emulsifier system, the product formed is not a microemulsion, but rather a mesophase-stabilized emulsion (the mesophase does not have separate oil and water phases). The disclosed compositions are said to provide mouth feel and texture benefits to food products. The emulsion particles formed in the '482 patent are relatively large (i.e., from about 2 to about 10 μm).
U.S. Pat. No. 6,426,078, Bauer et al., issued Jul. 30, 2002, describes oil-in-water microemulsions which comprise from 10% to 99% of a triglycerol mono fatty acid emulsifier (for example, triglycerol monolaurate, triglycerol monocaproate or triglycerol monocaprylate), 1% to 20% of a lipophilic substance (for example, beta-carotene, vitamin A or vitamin E), and water. These compositions are said to be useful in foods, cosmetics or pharmaceuticals for incorporating non-water-soluble (lipophilic) substances. There is no disclosure of a ternary surfactant emulsifier system for forming the microemulsion.
U.S. Pat. No. 6,444,253, Conklin et al, issued Sep. 3, 2002, describes a microemulsion flavor delivery system in the form of an oil-in-alcohol composition. These compositions require the use of alcohols which generally are not included in typical food or beverage formulations. Further, the '253 patent does not teach or suggest a ternary surfactant emulsifier system.
U.S. Pat. No. 6,509,044, Van Den Braak et al., issued Jan. 21, 2003, describes microemulsions of beta-carotene. These microemulsions are said to be based on an emulsifier system which preferably is a binary surfactant system, but can also be a ternary system (although there are no examples of a ternary system provided). It is taught that the fatty acid profiles of the emulsifiers are matched with the fatty acid profiles of the oily ingredient to be incorporated into the composition. There is no teaching in the '044 patent of a ternary high/low/medium HLB surfactant emulsifier system for use in forming the microemulsion.
U.S. Pat. No. 6,774,247, Behnam, issued Aug. 10, 2004, relates to aqueous ascorbic acid solutions. These solutions are said to contain an excess of an emulsifier having an HLB of from about 9 to about 18, such as polysorbate 80. There is no suggestion in the '247 patent to utilize a ternary surfactant emulsifier system.
U.S. Published Patent Application 2002/0187238, Vlad, published Dec. 12, 2002, relates to clear, stable oil-loaded microemulsions used as flavoring components in clear beverage compositions. These compositions utilize a co-solvent at a co-solvent:surfactant ratio of about 1:1. Further, the surfactant component comprises a mixture of at least two surfactants having an average HLB of from about 9 to about 18, preferably from about 12 to about 15. There is no disclosure in the '238 application of a ternary surfactant emulsifier composition comprising a mixture of low/medium/high HLB surfactants. The microemulsions defined in the '238 application comprise at least 30% oil, 1% to 30% of a surfactant mixture having an HLB of from 9 to 18, less than 20% co-solvent, and at least 35% water.
PCT Published Patent Application WO 94/06310, Ford et al., published Mar. 31, 1994, describes a colorant composition in the form of a microemulsion. Compositions disclosed in the '310 application include beta-carotene, alpha-tocopherol and ascorbic acid. Polysorbates are preferred emulsifiers in the '310 application. There is no teaching of a ternary surfactant emulsifier system in the formation of the microemulsion.